This invention relates in general to missile directional control systems and, in particular, to a method of providing a rate of change of attitude signal to a missile directional control system.
In the typical ballistic missile attitude control system, a signal related to the rate of change in the missile's attitude angle is required to implement the attitude control loop. Rate signals have in prior systems been obtained from a rate gyro or have been developed from the differentiation and filtering of resolver signals.
Both of the prior techniques have inherent disadvantages in attitude control systems. Rate gyros do no provide the required reliability unless they are used redundantly. The differentiation of resolver signals places tight performance requirements on the resolvers. The use of digital techniques with the resolvers results in quantization of the rate data which increases the slew rate requirements of thrust vector control systems and reduces flight control stability margins.